This invention relates generally to fixtures and more specifically to a fixture used for torquing a component of a fuel injector assembly.
Prior mechanical fuel delivery systems have provided improved power and efficiency for internal combustion engines. Recently, electronic technology has replaced the mechanical technology in fuel delivery systems to further improve the efficiency and operational characteristics of an internal combustion engine. However, as sophisticated electronic technology is increasingly incorporated in fuel delivery systems, field repair and maintainability of these systems have declined. As a result, fixtures for repairing fuel delivery system components have been required to match factory provided levels of efficiency and operational characteristics.
One example of such a component is the fuel injector for a diesel engine. Because diesel engines typically operate for more than five hundred thousand miles between major overhauls, field repair of diesel fuel injectors between overhauls is desirable to maintain factory provided levels of fuel metering. This is particularly true for diesel engines in the trucking industry which rely on high levels of fuel efficiency to keep operating costs at a minimum. Nozzle testers for diesel engines have been developed dating back to 1945. For example, U.S. Pat. No. 2,157,766 by Cole describes such a nozzle tester. Kiene, U.S. Pat. No. 2,857,759, discloses a diesel engine fuel injector testing device which mounts the fuel injector in a vertical position on a frame. In Kiene, the plunger, check valve, tip seal, or any test requiring oil pressure force through the injector, may be tested. Downs, U.S. Pat. No. 4,170,072, discloses a fuel injector adjustment fixture which permits the adjustment of a stop which limits the upward travel of a unit type fuel injector plunger.
While these devices address generally fixtures for fuel injectors of diesel engines, there is always a need for an improved fixture capable of repeating factory set assembly tolerances while being used in the field. Such a fixture should therefore be operable by the average diesel mechanic and provide assembly limits or checks to prevent damaging the fuel injector components. Such a fixture should also be self-contained and readily transportable to facilitate transport within the operating field. Such a fixture would further be adaptable for torquing components of the Cummins CELECT.TM. electronically controlled injectors for the full authority electronic fuel system of both the Cummins L10 and N14 model diesel engines.